Mosquitoes are the most important group of medically important insects, both from the viewpoint of the numbers of disease agents they transmit and the magnitude of the health problems the diseases create throughout the world. The current trend toward the use of control agents that are ingested by mosquito larvae emphasizes the urgent need for studies on the feeding behavior and nature of the dietary resources utilized by the larvae in natural habitats. This proposal is directed at furthering our knowledge in this area through a combined field and laboratory approach that will examine: 1) the feeding behavior of Aedes and Anopheles larvae in the natural environment; 2) the influence of the spatial and temporal distribution of dietary resources in tree hole and pond habitats on the size and number of adults; 3) the type and size of food ingested by Aedes and Anopheles larvae; and 4) the contribution of ingested dietary components to the growth of Aedes and Anopheles. Methodology will include: videotape analysis of feeding behavior, electron microscopy to examine mechanisms for capturing food particles, larval gut analysis, characterization of dietary resources by microbiological and chemical techniques, particle size analysis using x-ray diffraction, larval assimilation studies, tracer experiments, and pupal and adult size and production. Results from this study will provide valuable information on the diet, growth, and production of larval mosquitoes in their natural habitat, which can then be related to the longevity and vector potential of adults, and greatly assist in the formulation of new materials for field-use in the control of mosquito pest species.